Double spiral spring



April 1950 D. E. A. BONNEMORT 2,503,149

DOUBLE-SPIRAL SPRING Filed Nov. 24, 1945 7 QLL lllllllllll 'I.'HHHILIICIIZ mm wmmm. 715

B Inventor fi/zmz 5 MILE Aucusrm flow/15mm Patented Apr. 4, 1950 DQUBL'EL SPIRAL -SPBIN G DanielEmiI Augustin Bonnemort, Romainville,

France.

Applicatiom-NovemliemZi, 1945, Serial No; 630,5893: In-I'rancei-December:30;.1942;i

ScctionLRublicLaw 690; August8, 194s. Pa'tenhexpires December30; 1962 2 Claims.

This invention relates to a doubleespiralspringi.

more particularly, fore electric. circuit-breakers and change over switches.

Double-spiral springs are already known as"- that hasa tendency to make-the springmovetowards the-right is controlled by the knob or handlepf the switch-while -theend of the other elementary spiral controlsdireetly the contact pieces and is held stationary until a relative displacement is reached for which the switching is executed; the opposite operation is of course provided for a left-hand movement.

The advantage of the double-spiral spring for the above mentioned use is that it makes it possible to obtain the above described movement while accumulating a considerable energy in a minimum space.

However, the use of double-spiral springs of the usual construction with a circular section has various disadvantages which reduce the importance of the above quoted advantages:

1. A delicate machining owing to the fact that it is difiicult for the spring steel wire having a round section to coil in superposed turns.

2. An incomplete use of the actual work of the metal owing to the unequal deformation of the extreme and middle turns.

3. The tendency of the turns to interlock during the working of the spring.

On the other hand, fiat steel springs of various forms have already been used for obtaining the reciprocating movement in the above mentioned switches, but since said springs were arranged on a single turn they required the adjunction of One or more pieces for transmitting to the inner end of the spring the actions which in the case of a double-spiral spring are exerted directly upon either flange. This entails a more complicated and weaker construction.

The double-spiral spring according to the invention is formed of a continuous spring steel blade made in a single piece having a rectangular section and giving rise when coiled about one and the same axis to a spiral in one direction and to a second spiral in the contrary direction, both said spirals being juxtaposed on the same axis and parallel with each other, i. e. located in two difierent parallel planes, the inner turn of the spiral of one direction being deviated from its plane in its middle for forming in the plane of the adjacent turn of the contrary direction the thus interlocks corresponding inner: half turn' order? thus: to; provide for the inversion ofthe =direction;.

The rectangular section offers the advantage that tlie turns canno-t roll' uponr :onetancther.. and

The spring steel blade which forms: the doublesspiraliispring is a continuous'blad made: of: single-piece and deflected? imthe: vicinity of Titst. m'iddle for formingbotlr=spiral-s' ofl contrary diz-i rections, said spiralsbeings juxtaposed and i-i parallel witli each -otherythe' mediantdeviation: off the spring thus forming the 'conn ectionabetweemz both spirals without it being necessary to use an outer connecting member.

Appended drawings show a spiral spring adapted for use with an electric switch.

In said drawing:

Figure 1 is a front view of the double-spiral spring the outer ends of which are directed towards the top of the drawing.

Figure 2 is a similar view but after a rotation of 180 which has brought the outer ends to a position in which they are directed towards the bottom of the drawing sheet, and

Figure 3 is a side View of the double-spiral spring, the spirals being drawn apart deliberately in Order to show the part of the spring that has been deflected to serve as a connection between both spirals.

The double-spiral spring is formed of a continuous spring steel blade with a rectangular section a, b. Starting from end or flange a the blade is coiled according to a spiral A of one direction, the inner turn 0 being deviated from its plane in its middle according to a line which in order to facilitate the machining operation is a substantially straight line 11 (Figure 1) for forming in the plane of the juxtaposed parallel spiral B with the same axis as A the inner turn c (Figure 2) initiating the spiral B of the contrary direction terminating in the flange b. The controlling member of the switch, not shown, is adapted to act upon the flanges a and Z).

For making said spring one starts, for instance, from a steel wire having a circular section and that has been suitably flattened as, for instance, through a rolling operation. For coiling the spring the middle part of the so prepared wire is gripped in a driving jaw of any suitable construction by means of which the wire is given a coiling movement first towards the right for one of the sections of the spring and then towards the left for the other section, the machining operations being effected for the remainder in the usual well known manner.

The advantages insured by the invention are the following ones:

1. An easy machining owing to the possibility of coiling the turns fiat upon one another.

2. The optimum working of the metal owing to an equal deformation of nearly the totality of the metal fibres.

3. A free and easy working owing to the impossibility of a mutual interlocking of the turns without it being necessary to tighten the spring in a manner prejudicial to a good working of the same.

4. An identical stress with a great flexibility whatever may be the direction of working.

The spring can be made in all desired sizes and of any suitable material. Of course, it could be made, as well, through starting from a rectangular blade with sharp angles.

The invention is useful for electrical appliances and generally wherever it is desired to obtain an actuation with a quick release in one direction or the other.

I claim:

'1. A double coil spring for electric circuitbreakers, change-over switches and the like constituted by a single fiat spring blade spiralled first in one direction through substantially one half of its length and then into the other direction through substantially the other half of said blade, the two spiral halves being connected 30 through a short substantially flat portion of the blade, the outer ends of the two oppositely 4 spiralled halves of the blade being directed radially outwards for actuating purposes, the two halves being arranged coaxially in adjacent parallel planes.

2. A double coil spring for electric circuitbreakers, change-over switches and the like constituted by a single spring blade and comprising a first flat spiral having an outer end extending radially therefrom and an inner end extending out of the plane thereof, and a second flat spiral, coaxial with said first spiral and in a plane parallel thereto, and having an outer end extending radially therefrom, said inner end being common to both said spirals, and the turns of said spirals being respectively in opposite directions relatively to the common axis.

DANIEL EMILE AUGUSTIN BONNEMORT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 419,475 Rix Jan. 14, 1890 1,917,486 Beck July 11, 1933 FOREIGN PATENTS Number Country Date 9,654 Great Britain 1907 626,739 Germany Mar. 2, 1936 893,392 France Jan. 31, 1944 

